Fitness Trends

New Study Promotes Sleep Benefits of Exercise

March 4, 2013, 12:00AM

Do you ever have difficulty falling asleep or do you wake up frequently during the night? If you wake up during the night, do you then have difficulty returning to sleep? During the day have you ever encountered sleepiness, difficulty concentrating or irritability? These questions describe symptoms suffered by people with insomnia, or difficulty sleeping. Problems falling asleep and staying asleep plague a large number of us. According to the National Institutes of Health, about 30 to 40 percent of adults report symptoms of insomnia annually, and about 10 to 15 percent of adults say they have chronic insomnia. Sleep problems can be related to stress and worry, anticipation, drugs, increasing age, jet lag, shift work and major schedule changes. Now, according to new findings from the National Sleep Foundation, lack of exercise can also be added to that list.

The outcomes of the National Sleep Foundation’s 2013 Sleep in America® poll show a compelling association between exercise and better sleep. The following results were compiled after reviewing data from a sample of 1,000 adults between the ages of 23 and 60:

Exercisers say they sleep better.

Vigorous exercisers report the best sleep.

Non-exercisers are the sleepiest and have the highest risk for sleep apnea.

Less time sitting is associated with better sleep and health.

Exercise at any time of day appears to be good for sleep.

Exercisers Versus Non-exercisers

Even a small amount of any type of exercise can be beneficial for sleep. The respondents in the study who reported that they exercised regularly (i.e., vigorous, moderate or light intensity) also reported that they got better sleep compared to the non-exercisers. The exercisers were significantly more likely to say, “I had a good night’s sleep” every night or almost every night on work nights than non-exercisers. Also, more than three-fourths of exercisers (76 to 83 percent) say their sleep quality was very good or fairly good in the past two weeks, compared to only 56 percent of non-exercisers.

What is pertinent about these findings is that the subjects reported physical activity as any activity performed for at least 10 minutes. Therefore, simply adding a 10-minute walk to your daily routine could improve your chances of a getting good night’s sleep.

Exercise Intensity Matters

When the researchers broke down the respondents into those who participated in vigorous-, moderate- or light-intensity exercise, the vigorous exercisers fared better than the rest when it came to sleep quality. Compared to non-exercisers, vigorous exercisers were about twice as likely to report, “I had a good night’s sleep” every night or almost every night during the week. Vigorous exercisers also reported fewer sleep problems, commenting that they rarely or never (in the past two weeks) had symptoms associated with insomnia. In contrast, one-half of non-exercisers reported that they woke up during the night and nearly one-fourth had difficulty falling asleep every night or almost every night. The authors of this study defined vigorous activities as those that require hard physical effort such as running, cycling, swimming or competitive sports. Moderate-intensity activities were defined as activities that require more effort than normal such as yoga, tai chi, and strength training. Lastly, light activity was defined as walking.

If you are not already a vigorous exerciser, you can work toward higher intensities by starting with a daily 10-minute walk and then gradually working your way up to more intense activities like running or jumping rope. Being able to perform higher intensity exercise has other overall health benefits as well, such as burning more calories in a shorter period of time and enhancing aerobic fitness levels, so it is well worth the effort to progress to this type of activity.

Non-exercisers, Excessive Sleepiness and Sleep Apnea

Being sleepy during normal wake-time hours can interfere with safety and quality of life. For example, excessive sleepiness while driving is dangerous, and being irritable due to lack of sleep affects mood and leads to negative experiences throughout the day. Though sometimes feeling sleepy is normal, a state of chronic sleepiness is cause for concern.

Excessive sleepiness and sleep apnea are more common in non-exercisers compared to exercisers. In the sleep poll, approximately one quarter of non-exercisers qualified as “sleepy,” whereas exercisers reported only a 12 to 15 percent incidence of sleepiness using the same measurement scale. Sleep apnea (a serious medical condition in which a person stops breathing during sleep) occurs more often in non-exercisers than exercisers. Its symptoms include non-restful sleep, tiredness, snoring and high blood pressure. It is also associated with an increased the risk for heart disease and stroke. In their study, The National Sleep Foundation found that risk of sleep apnea in exercisers is half that of non-exercisers.

The takeaways from this portion of the study focus on the fact that regular exercise can help improve sleep to the extent that it reduces tiredness and improves quality of life during normal wake-time hours. Furthermore, people with sleep apnea are often overweight, so exercise can be a part of a healthy weight-loss program and potentially decrease sleep apnea incidence or severity.

Sit Less and Sleep Better

According to the Centers for Disease Control and Prevention, emerging evidence suggests that time spent sitting during the day, independent of physical activity, is related to increased risk for health problems such as obesity, cardiovascular disease and cancer. Now, as a result of the sleep poll, some experts may start recommending spending less time sitting to improve sleep quality. Those who sat for fewer than eight hours per day were more likely to say they had “very good” sleep quality than those who sat longer (22 to 25 percent compared to 12 to 15 percent). Furthermore, self-described “excellent health” was more common in subjects who spent fewer than 10 hours per day sitting, versus those who spent 10 hours or more sitting (25 to 30 percent versus 16 percent).

To improve sleep quality and overall health, limit the time you spend sitting each day. In addition to daily exercise, try standing at your work desk, getting up for short breaks, taking the stairs instead of the elevator, walking to a coworker’s desk to talk instead of using email and moving around as much as possible.

Exercising “Too Close to Bedtime” is a Myth

One of the most interesting findings from the sleep study challenges the long-held belief that exercising close to bedtime will disrupt sleep patterns. In fact, the National Sleep Foundation has amended its sleep recommendations for “normal” sleepers to encourage exercise without any limits to time of day as long as it’s not at the expense of sleep. The findings of the sleep poll suggest that exercise at any time seems to be better for sleep than no exercise at all. However, the authors caution that people with chronic insomnia who are being treated medically should continue to restrict late evening and night exercise, if this is part of their treatment plan.

Conclusion

Though the results of a poll are not proof of causation between the variables it considers, the trend observed in this study does seem to suggest that exercise improves sleep. Furthermore, more than half (57 percent) of the total sample reported that physical activity levels are typically less than usual after a night of poor sleep. Thus, not exercising and not sleeping can become a vicious cycle.

The bottom line is that the benefits of regular exercise on sleep quality are remarkable and should be considered by anyone who suffers from difficulties related to sleeping.

Looking for more healthy sleep advice? Check out tips from the National Sleep Foundation, including recommendations based on the results of this poll.

Sabrena Merrill, M.S., is an exercise physiologist and ACE Education Content Development Expert. A 20-year veteran of the fitness industry, she is a Level 1 CrossFit Trainer as well as an ACE-certified Personal Trainer, Health Coach and Group Fitness Instructor. Sabrena holds a bachelor’s degree in physical education (sport science) as well as a master’s degree in physical education/biomechanics from the University of Kansas. A former full-time faculty member in the Kinesiology and Physical Education Department at California State University, Long Beach, Sabrena has a passion for educating others about current fitness topics as evidenced through her work developing curriculum for continuing education programs, writing for fitness-related publications, creating educational videos and speaking to fitness professionals at conferences and workshops nationwide.

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